Steam-engine.



No. 63I,777. Patented Aug. 29, |899.

P. CUNNINGHAM.

STEAM ENGINE.

(Applicatin med Fab. 12, 189s., (No Model.) 3 Sheets-Sheet I.

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No. 63I,777. v Patented Aug. 29, i899,

' P. CUNNINGHAM.

STEAM ENGINE.

(Appueatinn med Feb. 12,A1 a9s.) (No Mod'el.) 3`Sheets-Sheet 9` v J i;

Patented Aug. 29, |899.

P. CUNNINGHAM.

STEAM ENGINE.

(Applilcmmmea Feb. i2, 189s.,

3 Sheets-Sheet 3.-

(N0 Model.)

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THE Nona UNITED STATES PATENT OFFICE. i

PATRICK CUNNINGHAM, oF NEw BEDFORD, MASSACHUSETTS, ASSIGNoR on THREE-IroURTI-Is'ro FRED D. STANLEY, 0E SAME PLAGE, AND WILLIAM A. wI-IITTLESEY, oF PITTSEIELD, MASSACHUSETTS; l

'STAM-NGIN'E.

SPECIFICATION forming part of nemers` Patent No. 631,777, dated August 29, 1899.

Application filed February 12, 1898. Serial No. 670,121. (Normodel.)

To all whom, it may concern: f

Be it known that I, PATRICK CUNNINGHAM, of New Bedford, in the county of Bristol and State of Massachusetts, have inventeda new and useful Steam-Engine, of which the following is a specification, reference being had to the accompanying drawings, in which- Figure lis a plan showing the preferred form of my engine with four cylinders adapted for driving two propellers. Figs. 2, 3, 4, and 5 are sections on the corresponding lines of Fig. l, and Fig. 6 is a section on line 6 6 of Fig. 5. Figs. 4, 5, and 6 arel on a larger scale. Fig. 7 is a diagram of a modified form of my engine. Fig. 8 is a section on line 8 S of Fig. 7.

The main feature of my invention is an engine comprising two pistons and their cylin` ders, two crank-shafts, mechanism connecting the two crank-shafts and compelling each to revolve at the Same rate as the other, but each in a direction opposite to that of the other, and valve mechanism to cause each piston to begin its stroke in one direction when the other begins its stroke in the opposite direction. This new type of engine is characterized by these three features:-First, the two pistons are so subjected by the action of the valve mechanism to the action of the steam or other fluid under pressure as to cause each to begin its right or left stroke as the other begins its leftor right stroke; secondly, each piston is connected to drive its crank-shaft in a direction opposite to that of the crank-shaft of the other, and, thirdly, the two crank-shafts are mechanically connected to compel each to revolve in a direction opposite to that of the other. For the most perfect operation the axes of the two pistons and their cylindersshould be in line; but this feature of my invention may be embodied as shown in Figs. 7 and 8, where the axes of the pistons and cylinders are not in line, for most of the advantagesV of this feature of my invention are in the modified form of my engine shown in Figs. 7 and 8, the main difference being that there is a'slight tendency to move the cylinders in the form shown in Figs. 7 and 8 which is not in the preferred form shown in the other figures.

The other features of my invention are the combination of the two crank-shaftsof my engine with a novel connecting mechanism fully described below; also, the combination of two cylinders side by side with two valvechests between the two cylinders, oneA of which is the supply-valve chest-for both of the cylinders, while the other is the exhaustvalve chest for both of the cylinders; also, the combination of two crank-shafts, a plurality of double-acting pistons for driving each crank-Shaft, and mechanism to compel each crank-shaft to revolve with the other, whether in opposite directions or in the same direction, for this feature of myinvention relates to the advantageous application of the power of the double-acting pistons and to giving each piston the function of controllingvthe v'strokes of 'all the others, and finally the combination, with the two crank-shafts,

Vwhether revolving in the same or in oppositedirections, of two driven shafts and means for connecting and disconnecting them', more fully described below as a fourth feature of my invention, particularly adapted for driving two propellers.

In Fig. l I haveshown the preferred form of my engine, in which the two pistons are in one cylinder, each piston moving away from the other during one stroke, but toward the other during'the next stroke, and eachalways kept opposed to the other through` the oppo- Sitely-revolving crank-shafts, as I will now describe more fully by reference to the drawings, in which A represents a cylinder and a a its heads. The two pistons B B' are fast, respectively, to their rods b b, which extend through stuffing-boxes in the heads a d and connect with the cross-heads b2 b3. The crosshead b2 is connected by pitman b4 with the crank-shaft D, and cross-head bilis connected by pitman b4 with crank-shaft D.v The two crank-shafts D D are suitably connected so that they must revolve in unisonas above explained, but the connecting means is a matter of indifference so far as concerns this feature of my invention. All this is Inost plainly shown in Fig. 2. The steam is supplied alternately at the middle of the cylinder, (between the pistons B B and at the ends IOO l haast-valve f.

A of the cylinder,) and the preferred means for applying and exhausting the steam is shown in Fig. 4, fully described below; but as any suitable means familiar to all skilled in the art may be used so far as this feature of my invention is concerned no furtherdescription of the means for applying and exhausting the steam is here necessary.

The operation is as follows: Starting with the pistons B B close together at the middle of the cylinder, as shown in Fig. 2, the force of the steam is exerted in forcing the pistons apart, each piston serving as an abutment against which the steam acts on the other, and the pressure on piston B is transmitted through rod ZJ and pitman b4 to shaft D, while the pressure on piston B is transmitted through rod b and pitxnan to shaft D; but

Aas the shafts D and D are so connected (by means shown in Fig. 3 or otherwise) that they must revolve in unison the power of both pistons may be applied to either shaft, and the speed of bothpistons must always be the same. At. the end of the outer strokes of the pistons B B the steam is exhausted from the middle of cylinder A and applied at each end when its power is exerted in forcing the pistons each to approach the other; but the pressure on the pistons is again transmitted, as before, to the shafts D D', so that in this form of my invention the pistons B B always react each on the other directly during the outer stroke and through the shafts D D during the inner stroke of each piston, while in the form shown in Fig. 7, in whichl the pistons are in separate cylinders, the pistons react against each other through the connections kbetween the crank-shafts, as will be clear from the drawings.

In Figs. l to 6 of the drawings I show a compound engine composed of four cylinders with two pistons in each, and it will be seen that the cylinders are arranged in pairs, with a supply and exhaust valve for each pair, as is best seen in Fig. 5. This is a wholly new construction, which has many advantages which will be apparent without detailed description, and this special combination of cylinders in pairs with a supply-valve and an exhaust-valve for each pair and preferably a pair of pistons in each cylinder is another feature of myinvention. As shown in the drawings, the two high-pressure cylinders A A are bores in a single vcasting A4, and this casting A4 has standards M, which are mounted on bed M', which is also shown as one casting provided with ribs for the standards M and f-or the ways m of the cross-heads b2 b3. Two otherv boresin the casting A*L are lined with the tubes F F', which fit steam-tight and receive the supply-valve fand the ex- These valves f and f are also tubes, which are connected by spiders, as best shown in Fig. 5, with the valve-rods fzfs, which are reciprocated by eccentrics on shaft D', as will be clear from Figs. l and 4. Tube F connects at one end to thc supplypipe F2, which leads from the boiler, and tube FH is connected at one end to the pipe F, which is the exhaust-pipe from high-pressure cylinders A A and the supply-pipe for lowpressure cylinders A2 A3. The operation of the supply-valve will be plain from the left of Fig. 6 and of the exhaust-Valve from the right of that figure. l Onthe left of Fig. 6 the steam iows in through pipe F2 and fills tube F and the interior of valve f, which when in the position shown has slightly opened the supply-ports leading to the ends of the cylinder A, and the further endwise motion of valve j' in the direction of arrow will open these end supply-ports wide, and the return motion of valve f will close them to cut off the supply at about half-stroke. Valvef has also slightly opened the middle supply-ports of cylinder A', and its further endwise motion will also open these ports wide and its return motion close them to cut o at about half-stroke. The further return of valvef will open and close the middle supply-ports of cylinder A and the end supply-ports of cylinder A. The exhaust-valve j" when in the position shown at the right of Fig. 6 has opened the middle exhaust-port of cylinder A2 and closedthe end exhaust-ports of that cylinder, for the pistons B B in cylinder A2 are then approaching each` other, but has opened the end exhaust-ports of cylinder As and closed the middle exhaust-port of that cylinder, for the 'pistons B B of cylinder A3 are then moving away from each other. The main advantages ot' this construction are the perfect balance obtained and also the fact that a film of steam when the valve is in use will force itself between the outer and inner tube, (for as the inner tube must be a running tit in the outer tube there is room for that film of steam, although the leakage is negligible when the tubes are properly fitted,) and for that reason, ,as well as the perfect balance, the power required to operate the Valve is materially less than in any other engine known to me.

The action and style of valves used on the modified form shown in Fig. '7 are similar to the action and style of the valvesabove described, except that the ports at the middle of the cylinder are done away with and the steam supplied and exhausted alternately at each end of the cylinder, as will be clear from Fig. 8.

The exhaust-steam from the high-pressure cylinders A A supplies the low-pressure cylinders A2 A3, a's will be plain, and the steam escapes into the open air or into a condenser through exhaust-pipe F4, Fig. 6.

This four-cylinder double compound engine rotates the two shafts D D each at the saine speed, but in opposite directions, which is essential in the marine engine which I have shown in my drawings when. used for driving two propellers which are right and left and must always rotate'in the opposite directions, and for that reason of course shafts D D must always rotate in opposite directions; but a IOO IIO

and thereby very greatly facilitate turning,.

and this while maintaining speed, for I do not reverse the engine of one propeller and thereby back with one and go ahead with the other, but simply disconnect one and by that act throw all the power of the engine on the other. This feature of my invention is shown in Fig. 1, where P is a propeller-shaft con- 'nected to shaft D by clutch p, and P a propeller-shaft connected to shaft D by clutch p'. These clutches are too well known to require detailed description and are connected and disconnected by familiar means, (indicated by the levers p2 and p3.)

The practical value of my new engine depends largely upon practical and efficient means for connecting the shafts D and D' so that they must revolve in unison, but in opposite directions, and I show in Figs. 1 and 3 a novel means of connecting them, which is also an 'important feature of my invention, and this feature consists in the combination of those two shafts by means of a crank d, whose pitman D reciprocates cross-head d2, which is connected by link d3 with one end of lever d4, the other end of that lever being connected by link (Z5 with a second cross-head d, which is connected by pitman CF with a crank d8 on shaft D'. In practice I use two of these connections, with the wrist -pins of their cranks ninety degrees apart, as this prevents all possibility of getting stuck on centers and also renders the transmission of the power of the engine through one shaft to the other more perfect, and this is especially important where the total power of the engine is to be delivered through one shaft only, for when both shafts are doing equal duty the connecting means has much less strain than when one shaft only is doing the duty of both, for when the two shafts are each doing equal duty the connecting means simply keep the two shafts and all the pistons in unison.

I am aware that two pistons and two crankshafts revolving in opposite directions are shown in combination with mechanism for cont-rolling the relative motions of the piston in patent to Nichols, No. 125,838, dated April 16, 1872, and I disclaim that engine, the essential difference being that in the Nichols patent the two pistons move part of the time in the same direction and part of the time in opposite directions, while in my engine one piston begins its stroke in one direction at the same moment that the other piston begins its stroke in the opposite direction, and while I do claim this latter feature as new in itself,

for I am aware that it is shown in several prior patents, (see, for example, No. 53,596, to Ferris, dated April 3, 1866, and No. 548,859, to Villiams, dated October 29, 1895,) yet'I am the first to combine the two features--that is, two pistons always opposed as to direction of movement and two crank-shafts always 0pposed as to directions of movements-and the combination of these two features is the lnain feature of my invention.

What I claim as my invention isl. In combination two pistons; their cylinders; valve mechanism to cause each piston to begin its stroke in one direction when the other begins its stroke in the other direction; two crank-shafts one driven in one direction by one piston and the other in the opposite.`

to move in a direction opposite to that of the other; two crank-shafts revolved in opposite directions by the pistons; and a mechanism two cross-heads, a lever between the two crossheads, and links connecting one end of that lever with one cross-head, and the other end of that lever with the other eross-head, all combined to cause the two crank-shafts to be driven in unison and in opposite directions substantially as described.

3. In an engine the combination of two cylinders side by sid e, a cylindrical supply-valve chest and a cylindrical exhaust-valve chest, side by side and between the two cylinders, two sets of supply-ports in the supply-valve chest; two sets of exhaust-ports in the exhaustvalve chest; a supply-valve in the supplyvalve chest, and an exhaust-valve in the eX- haust-valve chest, and means to actuate both the supply and the exhaust valves; all combined substantially as described.

4. In combination two crank-shafts; means for rotating each shaft; mechanism connecting them and compelling each to revolve with the other; two shafts, one driven by one crank-shaft the other by the other crankshaft and a friction-clutch connecting one crank-shaft with its driven shaft; a second friction-clutch connecting the other crankshaft with its driven shaft; and means to operate each clutch whereby the whole power of both crank-shafts can be applied to either driven shaft by disconnecting one of the friction-clutches and connecting the other as described.

PATRICK CUNNINGHAM.

lVitnesses:

WM. MAYNADIER, II. P. GUILLO.

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